The National Transportation Safety Board said Wednesday, January 15, that Boeing documented four prior failures in 2011 involving a component that secures MD-11 engines to the wings. The failures occurred on three aircraft originally built by McDonnell Douglas, which Boeing later acquired. At the time, Boeing concluded the issue did not pose a “safety of flight” risk.
Investigators have since found cracks in several of the engine-mount parts involved in the recent crash — damage that routine maintenance failed to detect. The components were last inspected closely in October 2021, and the aircraft was not scheduled for another detailed check for roughly 7,000 additional takeoffs and landings.
It remains unclear when the cracks began to form, but the incident echoes a 1979 disaster in Chicago, when an American Airlines DC-10—predecessor to the MD-11—lost an engine during takeoff, killing 273 people. That crash prompted a worldwide grounding of 274 DC-10s until investigators determined that improper maintenance, not a design flaw, caused the engine to detach.
In the current case, Boeing issued a service bulletin addressing the MD-11 issue, but unlike an FAA airworthiness directive, it did not require operators to make repairs. The FAA also did not issue its own directive.